Techniques for chunk-level client side encryption are provided. In a content-addressable storage system, a plurality of chunks is used to implement a hierarchical file system. The hierarchical file system supports both encrypted and non-encrypted volumes. A folders and files layer makes calls directly to a chunk system layer for operations involving non-encrypted volumes. The folders and files layer makes calls to a volume encryption layer for operations involving encrypted volumes. The volume encryption layer receives calls from the folders and files layer through an API that matches the API through which the chunk system layer receives calls from the folders and files layer.